Five Lessons From Designing Hundreds of Modular Terrain Files

Published November 5, 2026. Last updated November 5, 2026. By Chris Mooney.

Chris owns Wargame Geeks, the company behind Container City.

When I first started working on Container City, the idea was fairly straightforward: a collection of modular shipping containers that could be stacked, connected and rearranged into different tabletop layouts.

Playtest modular 3D-printed terrain early. Put a few pieces on the table and see where the miniatures can actually go.

It ended up becoming considerably more ambitious than I’d originally planned. What began with containers grew to include hab blocks, walkways, towers, industrial buildings, defensive barriers and all sorts of smaller pieces. The Kickstarter also unlocked far more additions than I expected, leaving me with hundreds of STL files to organise and a growing list of new pieces to design.

Along the way, I’ve had to think about a lot more than how the individual models look. They need to work together, print reliably and, most importantly, be useful during an actual game.

These are five things I’ve learned while developing the range, many of which I wish I’d considered a little earlier.

Key points

• Test rooftops and routes with the miniatures you’ll actually use.
• Set shared dimensions and connection points before expanding the range.
• Test-print tricky pieces early and give each STL variant a clear name.

1. Design for the tabletop

A terrain model can look excellent in a render but become surprisingly awkward once it reaches the table.

Players need to move miniatures between buildings, reach figures standing on rooftops and work out whether something is in cover. Large decorative details can catch sleeves or make it difficult to place models. Narrow platforms might look realistic but leave no room for a miniature’s base.

When I’m looking at a new design, one of the first things I consider is what players will actually be able to do with it. Developing Thrackdown, my own free miniature skirmish game, has made me even more conscious of this. It’s one thing to design a rooftop that looks good on screen, but quite another to be the player trying to move a miniature across it without knocking half the building over.

Does it block a firing lane? Can someone take cover behind it? Does it give players another way across the table, or create a position worth fighting over?

For Container City, I wanted buildings that could do more than provide something to hide behind. A container might block line of sight when placed at ground level, become an elevated firing position when stacked, or help form a route between two larger structures.

That versatility matters when players are building different layouts from the same collection.

None of this means terrain has to be plain. Pipes, panels, doors and damaged sections all help make a building feel like it belongs in the setting. They just need to stay out of the way of the people using it.

It’s also worth keeping a few miniatures with different base sizes nearby when planning gaming surfaces. Something that looks spacious on screen can feel considerably smaller once you put two or three fighters on it.

2. Modularity works better when you set some limits

One of the more important decisions when developing Container City was establishing consistent dimensions and connection points.

That might sound obvious, but it’s easy to start designing interesting individual buildings without considering whether they’ll work with everything else.

By keeping container footprints, heights and connection points consistent, I could keep adding new pieces without having to redesign the existing ones.

A walkway developed for one building might also connect to a completely different structure. Platforms can sit between container stacks, while new sections can extend an existing layout rather than replacing it.

If every building uses slightly different measurements, you quickly lose that flexibility. You end up with a collection of individual models rather than parts of a larger system.

There are practical limits too. Just because two pieces can technically connect doesn’t mean they make a sensible gaming surface. You still need enough room for miniatures, reasonably stable structures and clear access between different areas.

For anyone planning a modular terrain range, I’d suggest settling on a few standard widths, heights and connection points before getting too far into the design work.

It might restrict some of your early ideas, but it’s much easier than discovering halfway through a project that your latest walkway doesn’t quite meet the building it’s supposed to connect to.

A 150 mm LOUISWARE digital caliper can help you check a printed tab against the slot it needs to fit.

3. Vertical terrain needs routes, not just height

Stacking terrain is a relatively easy way to make a gaming table look more impressive. Making those upper levels enjoyable to play on takes a little more thought.

Players need practical ways to get their miniatures up there, and preferably more than one.

Ladders, stairs, ramps and walkways all help turn a tall building into a useful part of the battlefield. They also give players more decisions to make. Is the elevated firing position worth the effort of reaching it? Can another fighter approach from the side? Will taking the roof leave someone exposed?

I’ve found that connecting elevated areas tends to make them much more interesting.

A platform with a single ladder can create a useful bottleneck, but it also limits what players can do. Add a walkway to a neighbouring rooftop and another route down, and suddenly there’s a much larger area to fight over.

That was one reason I wanted Container City to include connecting walkways and platforms rather than simply providing buildings that could be stacked.

The height between levels is worth considering too. If climbing takes several turns, players may simply ignore the upper parts of the table. On the other hand, putting everything at roughly the same height can make the layout feel rather flat.

There’s no single measurement that will work for every game, but it’s worth thinking about how players are actually going to move between levels before deciding how tall everything should be.

4. Think about support-free printing from the beginning

Removing supports from a large terrain print is not something I particularly enjoy, especially when there are awkward pieces trapped inside doorways or windows.

For that reason, I try to make terrain support-free wherever possible.

It’s much easier to work around that requirement from the beginning than to finish a model and then discover it needs supports in half a dozen awkward places.

Door frames, damaged sections, windows and roof details all need to be considered alongside the intended printing orientation. Some details can be angled, others can be bridged, and occasionally it makes more sense to produce a separate component.

You also have to think about strength. A thin railing or decorative detail might print perfectly but still snap off the first time somebody catches it while moving a miniature.

Supports aren’t inherently bad. Modern slicers have become much better at handling complex shapes, including options such as organic supports. They’re extremely useful for miniatures and other detailed models.

But when somebody is printing enough terrain for an entire gaming table, reducing unnecessary supports can save quite a lot of filament, preparation time and cleanup.

If a test print leaves thin scraps of brim around the base, The Army Painter Plastic Frame Cutter can help trim them away before you check the fit.

Print-bed size is another consideration. I’ve tried to keep Container City accessible to people using smaller FDM printers, including providing split versions of some of the larger buildings. Not every piece will fit every machine, particularly the longer walkways, but it’s something worth considering during development rather than afterwards.

It’s also important to test how files print rather than relying entirely on what the slicer suggests. A model might look perfectly fine on screen, but there’s no substitute for seeing the finished piece.

The free Checkpoint Alpha terrain set was designed partly around this idea. It’s a small, usable collection of terrain that people can print without needing the rest of Container City. It also gives them an opportunity to see how the files work on their own printer before committing to anything larger.

For a test print on a machine that takes 1.75 mm filament, Polymaker Panchroma Matte PLA in Fossil Grey is one option.

5. File organisation becomes increasingly important

When you’re working with ten or twenty STL files, keeping track of everything is relatively straightforward.

When that grows into hundreds of files, it’s a different matter.

Container City includes different buildings, modular sections, interiors, damaged variants, alternative doors and numerous smaller components. Some pieces have multiple versions to accommodate different printing requirements.

Without a consistent naming system, it would be very easy for someone to spend more time searching for the correct file than actually preparing it to print.

I’ve tried to keep related files grouped together, with filenames that make it reasonably clear what each piece is and how it relates to the rest of the collection.

Preview images are useful too. If someone has to open six similar-looking files in their slicer to work out which one they need, the folder structure probably isn’t doing its job.

Updates create another challenge. As Container City has grown, I’ve continued adding new variants and improving existing designs. That means making sure people can identify newer versions without having to compare every file manually.

It’s worth thinking about this before the collection becomes enormous.

Setting up a sensible folder structure and naming convention at the start might not be the most exciting part of designing terrain, but renaming hundreds of files later is exactly as enjoyable as it sounds.

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